The present invention relates to imparting reversible color changes to waxes and candles as the temperature is raised, when the wax melts or when the candle burns.
Microencapsulated thermochromic dyes have been used in inks, paints, plastics, and in other vehicles. All hitherto reported thermochromic dyes on heating lose their color and become colorless if they are not microencapsulated or become white if they are microencapsulated, the whiteness being due to the cell wall of the microcapsules containing the thermochromic dye.
Thermochromic dyes undergo reversible electron transfer during heating cooling cycle. This reported mechanism, if correct, makes it generally unsuitable for use with most substrates without first microencapsulating them. The reason for this behavior is attributed to the delicate electron-transfer mechanism which becomes interfered with due to the effect of the substrate in question. It is, therefore, desired to convert this disadvantage of the unmicroencapsulated thermochromic dye into an advantage or to design a composition in which this problem is minimized or eliminated.